Oil collector in surge tank of refrigertion system



Oct. 19, 1954 s. P. SKOLI ET AL 2,691,873

OIL COLLECTOR IN SURGE TANK OF REFRIGERATION SYSTEM ,Filed Dec. 11, 1952 2 Sheets-Sheet 1 50 INVENTORS. I 45 6 mwzdi jkfi PazZ Jf/Yaow Oct. 19, 1954 s. P. SKOLI ET AL OIL COLLECTOR IN SURGE TANK OF REFRIGERATION SYSTEM 2 Sheets-Sheet 2 Filed Dec. 11, 1952 INVENTORS figbmzazd fia Patented Oct. 19, 1954 OIL COLLECTOR IN SURGE TANK OF REFRIGERATION SYSTEM Sigmund P. Skoli, Elmwood Park, Paul T. Moon,

Lombard, and Chester Witt, Deerfield, 111., assignors to Mojonnier Bros. 00., Chicago, 111., a corporation of Illinois Application December 11, 1952, Serial No. 325,262

6 Claims. 1

The present invention relates to a refrigeration system, and more particularly to a novel flooded type refrigeration system utilizing Freon or the ike.

Refrigeration systems of the above general type usually include a compressor, a condenser, an evaporator, and a surge drum into which liquid refrigerant, such as Freon, is introduced from the condenser and out of which gaseous refrigerant is returned to the compressor. The liquid refrigerant entering the surge drum is relatively warm as compared to the returning gases, and it is a primary object of this invention to provide a novel structure for effecting a, heat transfer between the relatively cool gases and the incoming liquid refrigerant, whereby to increase the efficiency of the refrigeration system.

A more specific object of this invention is to incorporate into the surge drum novel means for effecting heat transfer between relatively cool outgoing or returning gases and the incoming liquid refrigerant so as to provide a simple unit that can be economically manufactured.

In refrigeration systems of the above general type, oil generally becomes mixed with the liquid refrigerant in the compressor, and it is carried throughout the system. While a portion of this oil may be removed by an oil trap, complete removal of the oil from the liquid refrigerant is diificult to obtain, especially with such refrigerants as liquid Freon. The oil is thus carried to the surge drum where it normally accumulates since the oil separates from the refrigerant in the gaseous state and since only the gaseous refrigerant is returned to the compressor. It is, therefore, another object of the present invention to eliminate any excess oil accumulation in the surge drum by providing novel means for insuring a continuous return of any oil in the liquid refrigerant to the compressor.

Other objects and advantages of the present invention will become apparent from the following description and the accompanying drawings, wherein:

Fig. 1 is a side elevational view illustrating a refrigeration system utilizing the novel principles of this invention;

Fig. 2 is a Vertical cross section, showing a novel surge drum assembly embodying the principles of this invention;

Fig. 3 is a fragmentary vertical cross section taken along line 3-3 in Fig. 2;

Fig. 4 is a horizontal cross sectional View taken along line 44 in Fig. 3;

Fig. 5 is a perspective view illustrating a novel baflle means incorporated in the surge drum of this invention; and

Fig. 6 is a perspective view illustrating a heat exchanger element especially adapted for use in this invention.

Referring now more specifically to the drawings, wherein like parts are designated by the same numerals throughout the various figures, a refrigeration system embodying the principles of this invention is shown in Fig. 1. This system includes a compressor II], a condenser l2, an oil trap M in the conduit connecting the compressor and the condenser, a surge drum IS, a dehydrator IS in the line connecting the condenser and the surge drum, and a tank 20 having evaporator coils or pipes 22 disposed along the walls thereof. The compressor, condenser, oil trap, dehydrator, and tank may be of any conventional design and form no part of this invention. The tank 26, as illustrated, is of the cold Wall type which is often used for storing and cooling fluid foods, such as milk. However, it should be understood that the novel features of this invention may be applied to a refrigeration system designed for any desired purpose.

The novel surge drum assembly of this invention includes a tank or drum 24 which may be conveniently made in upper and lower sections welded together, as at 26. Relatively warm liquid refrigerant, such as Freon, is introduced into the surge drum adjacent its upper end and preferably generally axially thereof through an injector assembly which includes an inlet 23 adapted to be connected by suitable conduit means to the condenser. A strainer 30 of any suitable design is positioned within the inlet 28 to prevent clogging of the injector assembly. The inlet 28 communicates with a conduit which extends from the top to a point adjacent the bottom of the drum and is formed by means of a relatively short pipe section 32, a heat exchanger element 34, more fully described below, and a relatively long pipe section 36. The lower end of the conduit terminates in a nozzle assembly which includes a nozzle 38 of any desired formation for increasing the velocity of the liquid refrigerant. An outlet is provided centrally of the bottom of the drum by means of a pipe 40. Within the pipe Ml, there is welded or otherwise secured a venturi 42, and it should be noted that the end of the nozzle 38 extends partially into the enlarged mouth of the venturi.

The operation of the device as thus far described is as follows. The surge drum is filled with liquid Freon until the level reaches approximately the line 44. This level may be visually checked by providing a sight glass 4% of any conventional construction in the side wall of the drum. Upon operation of the compressor, relatively warm liquid refrigerant such as Freon is forced through the system and through the nozzle 38 and into the mouth of the venturi 42. It should be noted that the mouth of the venturi is also open to the interior of the drum, as at 45, and 50, so that as the fluid is injected into the venturi. from thenozzle, liquid is sucked from the drum through the venturi and the outlet pipe 40. By this means, a relatively great Volume of liquid refrigerant may be circulated through the evaporator coils as compared to the volume of refrigerant that is circulated through the compressor and condenser.

The injector assembly is supported at its upper end on a cover plate 52, which plate covers the upper end of a chamber formed by a relatively large diameter pipe section 55. The pipe section 54 is in turn supported within a seat 56 in cap 5% closing an opening in the upper end of the surge drum. It should be noted also that the chamber formed by the pipe section 54 is continued toward the interior of the surge drum by means of a tubular sleeve 58 Welded or otherwise fixed at its upper end to the cap. It should. also be noted that the sleeve to surrounds the heat exchanger element as so that gases returning from the interior of the surge drum to the compressor are directed into intimate contact with the heat exchange element as they pass upwardly through the sleeve 65, into the pipe section 54, and thence through outlet pipe G2, which outlet pipe is connected in any suitable manner to the compressor.

The refrigerant passes through the evaporator coils or pipes 22 and is returned to the surge drum by conduits B l and 66. It should be noted that these conduits communicate with the interior of the surge drum at points well above the liquid level 4 and also above the lower end of the sleeve baflie E8 includes a front wall 12 which extends substantially normally to the bottom. As shown best in Fig. 3, the baflie is proportioned so that the bottom It may be secured at its periphery to the inner surface of the surge drum as by welding at M, and the front wall extends upwardly along the sleeve Bil and, if desired, may be welded thereto. It should be noted that the bottom it is inclined a slight amount relative to the front wall so that the surface of the bottom slopes downwardly toward the center of the surge drum. On

both sides of the sleeve 60, the front wall 12 of the baiiie is formed with inwardly bent Wings 75 and '58 which are spaced from the interior walls of the surge drum to permit the gaseous refrigerant to be distributed throughout the interior of the drum. It should be noted that the wings l6 and it terminate at the bottom Hi to provide relatively shallow dams and 82. The liquid refrigerant dropping onto the bottom H3 accumulates until it overflows the dams 8 3 and 82 and drops to the bottom of the surge drum.

An important feature of this invention resides in the means for returning oil mixed with the liquid refrigerant from the surge drum to the compressor. This is accomplished by providing a small aperture as in the front wall 12 of the baffle adjacent the bottom It. By referring to Fig. 3, it is seen that this aperture 84 is located directly under the lower end of the sleeve so that a small amount of the liquid refrigerant hav through the sleeve to. and outlet 52.

in oil entrained thereinis discharged through the aperture and under the Send of'the sleeve.

This liquid refrigerant is picked up by the stream of gases entering the sleeve 6i! for return to the compressor. However, it is important from the standpoint of efiiciency to prevent the refrigerant in the liquid state from returning to the compressor, and, therefore, the particular type of heat exchange element 34 has been provided. The heat exchange element, which is shown in Fig. 6, includes a central tube 86 having high heat transferring characteristics and having a plurality of relatively thin fingers or filaments 88 radiating therefrom. These relatively small fingers provide tortuous passageways through which the gas and theliquid refrigerant .must flow. This not only insures intimate contactof the relatively cool gases with the heat exchange element for effecting heat transfer between said relatively cool gases and the incoming relatively warm liquid refrigerant passing through. the central conduit 86, but also breaks up the liquid passing out with the gases, whereby complete vaporigation of said outgoing liquid is insured. Since the oil entrained in the liquid refrigerant such as Freon is not miscible with Freon in the. gaseous state, the oil separates from the refrigerant and is carried by the gaseous stream through the outlet pipe 62 and back to the compressor, where it helps to lubricate the compressor. Since oil is continuously returnedto the compressor by this process, an undesirable accumulation of oil. in the surge drum is prevented.

While the operation of the above described apparatus is believed to be clear, a brief description of the functioning of the refrigeration system of this invention is as follows. The system is first filled with a liquid refrigerant, such as Freon, to the desired level 44. This level may be checked visually through the sight glass 36. Then, upon operation of the compressor, relatively warm liquid Freonis pumped from the condenser and from the nozzle 38 and into the venturi 4:2, additional liquid is drawn from the reservoir in the bottom of the surge drum through the Venturi.

and into the conduit Mi from which it passes into the evaporator tubes 22. The refrigerant emerges from the evaporator tubes in a partially liquid and partially gaseous state and enters the surge drum through the conduits 64 and 66. The gaseous part of the refrigerant flows around the front wall 12 of the baflie and into the interior of the surge drum, and thence out of the drum The relatively cool gases passing over the heat exchanger element 3 cool the liquid passing through the interior of the heat exchanger, thereby to increase the efficiency of the system. The liquid refrigerant returning to the surge drum through the conduits 6d and 56 drops onto the bottom ill of the baffle and then to the reservoir at the bottom of the surge drum. A small amount of the liquid refrigerant having oil entrained therein passes through the aperture 34 and into the returning stream of gases, wherein such liquid is vaporized, and the oil is separated therefrom and projected by the velocity of the gases to and out of the return pipe 62, as described above. 7

From the above description, it is seen that the present invention provides a simple highly efficient surge drum assembly, wherein the heat exchanger is made a part of the surge drum assembly in a manner to increase the efficiency thereof and to enable the assembly to be economically manufactured. Furthermore, it is seen that the present invention has provided simple and novel means for continuously removing oil entrained in the liquid refrigerant from the surge drum and returning such oil to the compressor.

While the preferred embodiment of the present invention has been illustrated and described herein, it is obvious that many changes may be made in the structural details of the preferred embodiment without departing from the spirit and scope of the appended claims.

We claim:

1. In a refrigeration system, means providing a surge tank chamber adapted to contain a body of liquid refrigerant, means for conveying liquid refrigerant from a source of liquid under pressure through an upper portion of said chamber and out of a lower portion of said chamber and for drawing liquid from the liquid body in said chamber out of said chamber for entry into an evaporator, conduit means within said chamber surrounding a portion of said last mentioned means adjacent an upper portion of said chamber for conveying relatively cool gases out of said upper portion of said chamber, and said portion surrounded by said conduit means including a heat exchanger element within said conduit means and above the level of said body of liquid refrigerant for effecting heat transfer between the relatively cool outgoing gases and the incoming liquid refrigerant.

2. In a refrigeration system, means providing a surge tank chamber having an inlet adjacent an upper portion thereof and an outlet adjacent a lower portion thereof, said chamber being adapted to contain a body of liquid refrigerant in said lower portion thereof, conduit means for conveying liquid refrigerant through said inlet from a source of liquid under pressure, said conduit means including a heat exchanger disposed substantially within an upper portion of said chamber and above the level of said body of liquid refrigerant, injector means connected with said conduit for discharging liquid from said conduit through said outlet and for drawing liquid from the lower portion of said chamber through said outlet for entry into an evaporator, means for directing relatively cool gaseous refrigerant in contact with said heat exchanger element, and means communicating with said last mentioned means for providing an outlet for said gaseous refrigerant from said chamber.

3. In a refrigeration system, a surge tank, conduit means entering an upper portion of said tank and extending toward a lower portion of said tank, said conduit means being adapted to convey a liquid refrigerant from a source of liquid under pressure through said tank, said tank being adapted to contain a body of liquid refrigerant in the lower portion thereof, means communicating with said conduit means and the lower portion of said tank for discharging liquid refrigerant from said conduit means and the lower portion of the tank for entry into an evaporator, means adjacent an upper portion of said tank providing an outlet for relatively cool gaseous refrigerant from said tank, and said conduit means including a heat exchanger element within the upper portion of said tank and above the level of said body of liquid refrigerant for 6 engagement by said relatively cool gaseous refrigerant to effect exchange of heat between said gaseous refrigerant and the liquid refrigerant passing through said conduit.

4. In a refrigeration system, a surge tank adapted to contain a body of liquid refrigerant in a lower portion thereof, means for circulating said liquid refrigerant from said tank to an evaporator, means providing an inlet in an upper portion of said tank for refrigerant in gas and liquid phases returning from an evaporator, means providing a restricted passageway within the upper portion of said tank and above the level of said body of liquid refrigerant for permitting refrigerant in the gas phase to escape from an upper portion of said tank, means for directing refrigerant in the liquid phase returning to the tank through said inlet into the gases escaping through said passageway, and a plurality of finger means within said chamber and in said passageway providing tortuous paths through which the gas and the liquid refrigerant entrained therein must pass so as to insure vaporization of the liquid refrigerant entrained in the gases to separate any oil from said last mentioned liquid refrigerant.

5. In a refrigeration system, a surge tank adapted to contain a body of liquid refrigerant in a lower portion thereof, conduit means entering an upper portion of said tank and extending into said lower portion, said conduit means being adapted to be connected to a source of liquid refrigerant under pressure, injector means communicating with said conduit means and said lower portion of the tank for circulating liquid refrigerant from said conduit means and the lower portion of said tank to an evaporator, means providing an inlet in an upper portion of said tank for refrigerant in gas and liquid phases returning from an evaporator, means providing a restricted passageway surrounding a portion of said conduit means in the upper portion of said tank for permitting refrigerant in the gas state to escape from the tank, said portion of said conduit means including a heat exchanger element within said chamber and above the level of said body of liquid refrigerant to effect an exchange of heat between the escaping gas refrigerant and the liquid passing through said conduit means, and means for directing a portion of the liquid refrigerant returning to said tank through said inlet into the gas refrigerant escaping through said passageway so that any oil in said last mentioned liquid refrigerant is removed from said tank.

6. In a refrigeration system, as defined in claim 5, wherein said heat exchanger element includes means for providing a plurality of tortuous paths through said passageway, whereby intimate contact of the escaping gas refrigerant is secured with said heat exchanger element and whereby vaporization of the liquid refrigerant entrained in said escaping gas refrigerant is assured.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,836,318 Gay Dec. 15, 1931 1,958,087 Hoffman May 8, 1934 2,051,756 Tolk Aug. 18, 1936 2,364,783 Goddard et a1 Dec. 12, 1944 

